Rod attachment assembly for occipital plate

ABSTRACT

The present disclosure relates, according to some embodiments, to orthopedic implantable device technology, and more specifically to implantable devices for use in stabilizing the occipitocervical junction and the cervical spine. For example, the disclosure relates to embodiments of an implantable orthopedic assembly generally comprising an occipital plate and one or more repositionable clamping assemblies for securing a stabilizing rod at a nonzero distance from a plate surface. One or more rails may extend laterally from a plate to support a clamping assemblies.

CROSS REFERENCE TO RELATED APPLICATION(S)

This is a divisional application of U.S. application Ser. No.13/767,403, which was filed on Feb. 14, 2013 and is incorporated hereinby reference.

FIELD OF THE DISCLOSURE

The present disclosure relates, in some embodiments, to orthopedicimplantable device technology, and more specifically to implantabledevices for use in stabilizing the occipitocervical junction and thecervical spine.

BACKGROUND OF THE DISCLOSURE

In the human body, the lower back portion of the skull is known as theocciput, and the neck vertebrae located closest to the skull are knownas the cervical spine. Critical neurological and vascular structuresdescending from the brain into the spinal column pass through thejunction between the skull and the cervical spine (the occipitocervicaljunction). When disease or traumatic injury threatens the stability ofthe cervical spine and/or the occipitocervical junction, surgicalintervention may be required to protect these critical structures.

Implantable occipitocervical fixation systems that provide stabilizationand/or promote fusion of the occipitocervical junction are known in theart. However, existing systems may be difficult and time-consuming toadjust, and often fail to provide desirable configurability options.

SUMMARY

Accordingly, a need has arisen for improved an implantableoccipitocervical fixation system that simplifies and streamlinessurgical placement procedures and provides greater configurability toaccommodate varying patient anatomies during surgical placement.

The present disclosure relates, in some embodiments, to orthopedicimplantable device technology, and more specifically to implantabledevices for use in stabilizing the occipitocervical junction and thecervical spine. For example, the disclosure relates to embodiments of animplantable orthopedic assembly generally comprising an occipital plateand one or more repositionable clamping assemblies (e.g., rod attachmentassemblies) for securing a stabilizing rod at a nonzero distance from aplate surface. One or more rails may extend laterally from a plate tosupport a clamping assembly. In some embodiments, an implantableorthopedic assembly may comprise (a) an occipital plate comprising a topsurface and a bottom surface, the bottom surface of the occipital plateadapted for securing to an occiput, (b) at least one rail extendinglaterally from a proximal portion of the occipital plate, the at leastone rail comprising a top surface and a bottom surface, and/or (c) atleast one repositionable rod attachment assembly adapted to enclose aportion of the at least one rail, the rod attachment assembly furtheradapted for securing a portion of a stabilizing rod at a distance fromthe at least one rail. A rod attachment assembly may comprise, in someembodiments, (1) a slide body comprising a rail aperture adapted tofrictionally contact at least one surface of the at least one rail, theslide body further adapted for lateral repositioning between a firstrail position and a second rail position, (2) a saddle body adapted forrepositioning between a first rotational position and a secondrotational position, the saddle body further adapted to receive theportion of the stabilizing rod, (3) a retention ring positioned on(e.g., contacting) an outside circumference of the saddle body (e.g., anoutside circumference of a circumferential recess in the saddle body)and positioned on (e.g., contacting) an inside circumference of theslide body (e.g., an inside circumference of a circumferential recess inthe slide body), the retention ring adapted to secure the saddle body tothe slide body, (4) a pressure cap adapted to maintain alignment betweena stabilizing rod and a saddle body (e.g., a corresponding stabilizingrod slot on the saddle body) and transfer an immobilizing force from thereceived portion of the stabilizing rod to the top surface of the atleast one rail, the immobilizing force immobilizing the rod attachmentassembly at a fixed rail position and in a fixed rotational position.

According to some embodiments, an occipital plate may comprise (e.g.,further comprise) at least one groove scoring at least one of the topsurface of the occipital plate or the bottom surface of the occipitalplate, the at least one groove adapted to facilitate contouring of theoccipital plate. Grooves may or may not be aligned (e.g., parallel) toeach other. For example, an occipital plate may comprise a first grooveand a second groove, with the second groove substantially orthogonal tothe first groove.

An implantable orthopedic assembly, according to some embodiments, maycomprise a plurality of apertures variably distributed across anoccipital plate, wherein the plurality of apertures penetrates both thetop surface of the occipital plate and the bottom surface of theoccipital plate, and wherein at least one of the plurality of aperturesis adapted to receive at least one bone fastener (e.g., bone screw), theat least one bone fastener adapted to secure the bottom surface of theoccipital plate to the occiput. Apertures may independently have anydesired shape. For example, a plurality of apertures may comprise asubstantially circular first aperture centered about a first aperturecenter axis. Each aperture axis may be independently non-orthogonal toat least one of the top surface of the occipital plate and the bottomsurface of the occipital plate. In some embodiments, a plurality ofapertures may comprise at least one countersunk aperture.

An implantable orthopedic assembly may comprise at least one instrumentinterface adapted to facilitate manipulation of the occipital plate withan instrument, according to some embodiments. For example, an occipitalplate may comprise an edge surface connecting a top surface of theoccipital plate and a bottom surface of the occipital plate, wherein theat least one instrument interface comprises a notch in the edge surfaceof the occipital plate.

In some embodiments, an implantable orthopedic assembly may comprise anoccipital plate having a longitudinal axis parallel to the plane of theoccipital plate and defining a first side of the occipital plate and asecond side of the occipital plate. An occipital plate may comprise, insome embodiments, at least one rail comprising a first rail and a secondrail, for example, the first rail extending from the first side of theoccipital plate, the second rail extending from the second side of theoccipital plate.

A slide body of a repositionable rod attachment assembly, according tosome embodiments, may be adapted for infinite lateral repositioningbetween a first rail position and a second rail position. A saddle bodyof a repositionable rod attachment assembly may be adapted for infiniterotational repositioning between a first body position and a second bodyposition, according to some embodiments. A repositionable rod attachmentassembly may comprise (e.g., further comprise) a loading componentadapted to exert a stabilizing force on a pressure cap, the stabilizingforce stabilizing the repositionable rod attachment assembly at anadjustable rail position and in an adjustable body position. A slidebody may comprise a slot that is adapted to at least partially enclose aportion of a rail (e.g., the at least one rail). A rod attachmentassembly may comprise (e.g., further comprise) a loading component(e.g., wave spring) adapted to be positioned between (e.g., inmechanical communication with) a saddle body and a pressure cap. Apressure cap may comprise, in some embodiments, a groove at one endadapted to contact at least a portion of a received portion of astabilizing rod. According to some embodiments, an implantableorthopedic assembly may comprise a retaining element that is adapted tobe attached to a plate rail and block egress from the plate rail (e.g.,prevent a slide body from sliding off an end of the rail).

According to some embodiments, the present disclosure relates to methodsof constructing an implantable orthopedic assembly. For example, amethod may include constructing an implantable orthopedic assemblycomprising an occipital plate, at least one rail rigidly coupled to andextending laterally from the occipital plate, and/or at least onerepositionable rod attachment assembly enclosing a portion of the atleast one rail, the at least one repositionable rod attachment assemblyadapted for securing a received portion of a stabilizing rod. A methodmay comprise, in some embodiments, (a) positioning a pressure cap of arepositionable rod attachment assembly within a receptacle of a saddlebody of the at least one repositionable rod attachment assembly, (b)positioning a surface of the at least one rail against a surface of aslide body of the at least one repositionable rod attachment assembly,(c) installing a retention ring in the slide body, (d) uniting thesaddle body with the slide body, wherein the at least one rail contactsthe pressure cap, and/or (e) securing the slide body to the saddle bodywith the retention ring. According to some embodiments, a method maycomprise positioning a loading component between the pressure cap andthe saddle body of the at least one repositionable rod attachmentassembly, wherein the loading component is adapted to exert a bias onthe pressure cap against the at least one rail to stabilize the at leastone repositionable rod attachment assembly at an adjustable railposition and in an adjustable body position.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the disclosure may be understood by referring, inpart, to the present disclosure and the accompanying drawings, wherein:

FIG. 1A illustrates a perspective view of an occipital-cervical fixationassembly according to a specific example embodiment of the disclosure;

FIG. 1B illustrates a perspective view of an occipital-cervical fixationassembly according to a specific example embodiment of the disclosure;

FIG. 1C illustrates a section view of an occipital-cervical fixationassembly according to a specific example embodiment of the disclosure;

FIG. 1D illustrates a section view of an occipital-cervical fixationassembly according to a specific example embodiment of the disclosure;

FIG. 1E illustrates an exploded view of a rod attachment assemblyaccording to a specific example embodiment of the disclosure;

FIG. 1F illustrates a perspective view of a rod attachment assemblyaccording to a specific example embodiment of the disclosure;

FIG. 1G illustrates a section view of a rod attachment assemblyaccording to a specific example embodiment of the disclosure;

FIG. 2 illustrates an elevation view of a rod attachment assemblyaccording to a specific example embodiment of the disclosure;

FIG. 3 illustrates an elevation view of a rod attachment assemblyaccording to a specific example embodiment of the disclosure; and

FIG. 4 illustrates an elevation view of a rod attachment assemblyaccording to a specific example embodiment of the disclosure.

Table 1 below includes the reference numerals used in this application.The thousands and hundreds digits correspond to the figure in which theitem appears while the tens and ones digits correspond to the particularitem indicated. Similar structures share matching tens and ones digits.

FIG. 1 Occipital Plate System 100 Plate 110 Aperture 111 Upper Surface112 Lower Surface 113 Groove 114 Projection 115 Narrowing 116 Rail 117Pin Hole 118 Retention Pin 120 Rod Attachment Assembly 130 Slide Body140 Recess 141 Rail Aperture 142 Retention Ring 150 Saddle Body 160Axial Channel 161 Locking Threads 162 Stabilizing Rod Slot 163 Shoulder164 Recess 165 Wave Spring 170 Pressure Cap 180 Pressure Cap Surface 181Flange 182 Upper Flange Surface 183 Groove 184

DETAILED DESCRIPTION

The present disclosure relates, in some embodiments, to an implantableorthopedic assembly generally comprising an occipital plate and one ormore repositionable clamping assemblies for securing a stabilizing rodat a nonzero distance from a plate surface. One or more rails may extendlaterally from a plate to support a clamping assembly.

Embodiments of a clamping assembly may comprise a base component (e.g.,a slide body), a body component (e.g., a saddle body), and a lockingcomponent (e.g., a pressure cap). When unlocked, a clamping assembly maybe laterally repositioned along a supporting rail and may also berotationally repositioned. Locking occurs when a stabilizing rod issecured in a clamping assembly. The rod exerts a force upon the lockingcomponent, causing the locking component to exert a force upon thesupporting rail. This force pulls a surface of a base component into asurface of a rail, effectively locking the base component at a fixedposition. A clamping assembly may further comprise a loading component(e.g., a spring) to exert a stabilizing force on the locking component,keeping the clamping assembly positionally stable while adjustments aremade prior to locking.

Some embodiments of the disclosure are illustrated in FIG. 1A (upperperspective view), FIG. 1B (lower perspective view), FIG. 1C (sectionview), FIG. 1D (section view), FIG. 1E (exploded view), FIG. 1F (upperperspective view), FIG. 1G (section view).

Occipital Plate

In some embodiments, an occipital plate may be of any size and shapeappropriate for being secured to an occiput. For example, an occipitalplate may be configured to provide a rod spacing of about 20 mm to about30 mm, about 30 mm to about 40 mm, or about 40 mm to about 50 mm. Forexample, when rod attachment assemblies are spaced at their outer mostlocation, the rods are approximately 50 mm apart and when they are attheir closest spacing the rods are approximately 40 mm apart for a 40-50mm plate assembly. An occipital plate may be generally planar with anupper and lower surface, in some embodiments. An occipital plate may bemade, according to some embodiments, from any material suitable forimplantation into the body, including, for example, stainless steel,titanium, ceramic, PEEK, a composite material, and/or combinationsthereof.

According to some embodiments, a disclosed assembly may be connected toone or more rods that are also connected to one or more cervicalvertebrae. These rods may be connected to the cervical vertebra throughthe use of pedicle screws, such as the screws described in U.S. Pat. No.6,540,748 and U.S. Published Patent Application No. 2010/0256681, bothof which are owned by Blackstone Medical, Inc. and which areincorporated herein by reference.

An embodiment of occipital plate 110 is illustrated in FIG. 1A. Asshown, occipital plate 110 is generally planar with an upper surface 112and a lower surface 113. An occipital plate may support one or more rodattachment assemblies 130. An occipital plate may be secured to anocciput, and a stabilizing rod (not shown) may be secured in one or morerod attachment assemblies 130 to provide stabilization and/or promotefusion of the occipitocervical junction according to some embodiments.

Rails

An occipital plate may include, in some embodiments, one or more railsto bear one or more rod attachment assemblies. The shape and/or numberof rails may be arranged around a point or axis (e.g., a central pointor central axis). Each rail may run radially, laterally, longitudinally,and/or in any other direction. Each rail independently may be of thesame and/or different length and/or with compared to other rails, insome embodiments. For example, two rails in symmetrical positions on aplate may have the same length and width. A rail may have a proximal enddefined by a narrowing in plate body width and/or thickness, relative tothe adjacent portion of the plate. A narrowing may be configured torestrict movement of a rod attachment assembly along a rail, forexample, movement toward a central plate axis. A rail may include, at oradjacent to its distal end, a retention structure configured to limitmovement of a rod attachment assembly along a rail, for example,movement away from a central plate axis. A retention structure maycomprise a thickening in a rail in some embodiments. A retentionstructure may comprise, according to some embodiments, a retention pin,for example, installed in a pin hole and protruding from a rail.

Rails may be located on a proximal portion of occipital plate 110. Forexample, as shown in FIGS. 1A and 1B, occipital plate 110 may includetwo opposed rails 117. Each rail 117 has a narrowing 116 at its proximalend and a pin hole 118 at its distal end configured to accommodateretention pin 120. Narrowing 116 is depicted here as a narrowing inthickness, but rail 117 may be narrowed in thickness and/or widthcompared to the adjacent portion of plate 110. Although two rails areillustrated, embodiments are contemplated in which a plate comprises onerail, three rails or more than three rails.

Projections

An occipital plate may include one or more projections in someembodiments. The shape and/or number of projections may be arrangedaround a point or axis (e.g., a central point or central axis).Projections, according to some embodiments, may extend radially,laterally, longitudinally, and/or in any other direction. Eachprojection independently may be of the same and/or different lengthand/or with compared to other projections, in some embodiments.

Projections may be located on a distal portion of an occipital plate.For example, as shown in FIGS. 1A and 1B, occipital plate 110 mayinclude one central projection 115 at its proximal apex and two opposedlateral projections 115. Although three projections are illustrated,embodiments are contemplated in which a plate comprises one projection,two projections, four projections or more than four projections.

Apertures

A plate may also comprise one or more apertures for receiving bonefasteners that may secure the plate to the occiput. Apertures may becircular or non-circular, may be countersunk, and may be orthogonal ornon-orthogonal to the plate.

As shown in FIGS. 1A and 1B, multiple apertures 111 may be located onoccipital plate 110. One or more such apertures may be arranged in anyconfiguration across occipital plate 110. Such apertures may penetrateboth upper surface 112 and lower surface 113, and may provide forattachment of occipital plate 110 to the occiput with bone fasteners(not shown) such as bone screws, pins, staples, or any other appropriatefasteners. An aperture 111 may be circular, oval, polygonal, or anyother shape about a center axis that is suitable to accommodate anappropriate fastener.

Furthermore, the center axis of an aperture 111 may be orthogonal to thesurface of occipital plate 110, such that a bone faster seated withinaperture 111 enters the occiput orthogonally, or the center axis of anaperture 111 may be non-orthogonal to the surface of occipital plate110, such that a bone faster seated within aperture 111 enters theocciput at an acute angle, providing for more contact between bone andfastener. In addition, aperture 111 may be countersunk such that thehead of a bone fastener seated within aperture 111 is flush with orrecessed from the top surface of occipital plate 110. Aperture 111 mayalso be counter-bored or otherwise shaped to accommodate a variety ofbone fasteners. Multiple apertures 111 distributed across occipitalplate 110 may be of uniform size and shape or may be of variable (e.g.,independently variable) size and shape.

It is contemplated that occipital plate 110 may not utilize anyapertures 111. In such embodiments, other methods of securing theoccipital plate to the occiput are employed. For example, the occipitalplate may be secured to the occiput with an adhesive, or fixationelements that penetrate the occiput may be integrated with the occipitalplate, thereby eliminating the need for separate bone fasteners.Furthermore, notches or other guide features for interfacing withinstruments external to occipital plate 110 may be located on occipitalplate 110. Such instrument interfaces may allow a tool to be attached tofacilitate placement, adjustment, and other manipulation of occipitalplate 110.

Grooves

Embodiments of an occipital plate may comprise grooves for facilitatingcontouring of the plate. A plate may also comprise notches or otherinstrument interfaces for facilitating manipulation of the plate priorto and/or during placement.

Grooves 114 may be scored into upper surface 112 and/or lower surface113 of occipital plate 110, for example, to provide for easier and moreprecise contouring and reshaping of occipital plate 110. Such grooves114 may allow better correlation with the surface of the occiput.Grooves 114 may be of varying length, width, and depth, and may extendradially, laterally, longitudinally, or in any other direction. AlthoughFIGS. 1A, 1B, and 1C illustrate occipital plate 110 with multiplegrooves 114, an occipital plate 110 with a single groove 114 or nogrooves 114 is contemplated.

Each rail 117 comprises a pin hole configured to fixedly or movablyhouse corresponding retention pin 120. For example, retention pin 120may be mounted in a position (e.g., a fixed position) protruding fromsurface 112 and/or 113. Retention pin 120 may alternatively beretractable within pin hole 118 and configured to have a deployedposition in which it protrudes from surface 112 or 113 and an undeployedposition in which it protrudes from neither surface 112 or 113. Rings,springs, detents, or other suitable means may be used to hold pin 120 inits deployed position and/or undeployed position.

Clamping Assembly

Rod attachment assembly 130 may be of any size and shape appropriate forsecuring a stabilizing rod to an occipital plate, and may be made fromany material suitable for implantation into the body, such as stainlesssteel, titanium, ceramic, PEEK, or a composite material. Rod attachmentassembly 130 comprises slide body 140, retention ring 150, saddle body160, wave spring 170, and pressure cap 180. Slide body 140 definesaperture 142 sized to accommodate (e.g., slidably accommodate) rail 117.Slide 140 incorporates a clearance fit with a rail such that rodassembly 130 can move within a confined space between an undercutportion of a plate and a retention pin. Wave spring 170 is sandwichedbetween pressure cap 180 and a bore in saddle body 160 such that thespring applies force to pressure cap 180 causing a friction fit betweenthe plate, slide, and pressure cap so force (e.g., light force) needs tobe applied to slide rod attachment assembly 130 along a plate.

Slide Body

In some embodiments, a rod attachment assembly may include a slide bodyhaving a central rail aperture sized and shaped to receive a plate rail.A central aperture may surround, according to some embodiments, anengaged plate rail. A rail aperture may define a lateral axis of a slidebody. A lateral axis may be parallel to a lateral (or radial) axis of arail with which it is engaged. A slide body may have an apertureperpendicular to a rail aperture configured to receive, for example, asaddle body. A slide body aperture may include a recess, for example,around the circumference of the aperture. A slide body aperture recessmay be configured to receive at least a portion of a retention ring. Aslide body aperture recess may be positioned within the aperture suchthat it aligns with a corresponding recess in an engaged saddle body. Aslide body aperture recess and a corresponding saddle body recess,together with an engaged retention ring may configured to positionand/or hold a saddle body within a desired distance (e.g., a fixeddistance, a pre-selected distance, a variable distance within a definedrange) of an engaged rail, in some embodiments. As shown in FIG. 1C, forexample, slide body aperture recess 141, retention ring 150, and saddlebody recess 165 together may position and hold slide body 140 and saddlebody 160 together and hold saddle body at a distance from rail 117.

Saddle Body

Saddle body 160 incorporates slot 163 (e.g., to receive a rod) andlocking thread 162 (e.g., to receive a set screw to clamp the rod tosaddle body 160 and/or rod attachment assembly 130). As a set screw istightened to secure a rod, pressure cap 180 forces an associatedoccipital plate rail 117 against slide 140's plate interface bottomsurface, locking the position of rod attachment assembly 130 along theoccipital plate rail 117. Saddle body 160's orientation issimultaneously locked such that rotation of saddle body 160 about itsaxis is locked. This is the result of saddle body 160 being pulledupward forcing retention ring 150 against the upper surface of recess141 in slide 140 in which the retention ring 150 is housed.

Pressure Cap

According to some embodiments, a rod attachment assembly may include apressure cap. For example, saddle body 160, in some embodiments, maycomprise axial channel 161 configured to receive wave spring 170 and/orpressure cap 180. According to some embodiments, a pressure cap mayslide within an axial channel of a saddle body (e.g., up and down withrespect to the plane of an associated plate).

In some embodiments, a pressure cap may have any shape including, forexample, a generally cylindrical shape. Its center or core may be solidor hollow, as desired. It's lower end may be configured to contact aplate rail (e.g., on a lower surface). For example, the lower (outer)circumference may include a flange configured to increase the contactsurface area. A flange may include an upper surface configured tocontact a spring (e.g., a wave spring). An upper end of a pressure capmay include a groove or detent configured to engage a set screw and/or arod. For example, as shown in FIG. 1C, pressure cap 180 has hollow coreand includes lower surface 181, flange 182, wave spring surface 183, andgroove 184. If rod engagement cut out geometry 184 is incorporated onpressure cap 180, some orientation control of that geometry relative toslot 163 may be beneficial. Pressure cap 180 may only contact saddlebody 160 in regard to orientation (rotation control). A pressure cap maybe cylindrical with two milled flats that are perpendicular to the cutout that accepts the rod in some embodiments. Any desirable means forensuring a pressure cap cut out is aligned with the slot in the saddlebody to enable proper rod engagement may be used, according to someembodiments.

Retention Ring

According to some embodiments, a rod attachment assembly may include aretention ring configured, for example, to engage a slide body and/orsaddle body. A retention ring may be configured to have a desired orrequired rigidity against forces perpendicular to the plane of the ring.In some embodiments, a retention ring may be configured to deform topermit insertion and/or engagement of a saddle body. For example, aretention ring may have radial elasticity and/or resilience.

Loading Component

A rod attachment assembly, in some embodiments, may include a loadingcomponent configured, for example, to resist axial forces and/or axialmovement of a pressure cap (e.g., resist longitudinal forces and/ormovement that would otherwise tend to bring pressure cap into closerproximity to a saddle body). For example, a loading component maycomprise spring 170 positioned between pressure cap 180 and saddle body160 and configured to resist movement and/or forces that would otherwisebring pressure cap flange surface 182 into closer proximity to saddlebody shoulder 164.

In some embodiments, a loading component may exert a stabilizing forceon a locking component to keep a rod attachment assembly positionallystable prior to locking. Such a loading component allows for moreprecise lateral and rotational positioning of rod attachment assembly130. In the embodiment illustrated in FIG. 1C, the loading component 170is represented by a wave spring located between saddle body component160 and pressure cap 180. Wave spring 170 exerts a light pressure onpressure cap 180 to act as a load to the system. This load imparts afriction to the system, keeping rod attachment assembly 130 positionallystable. Although a wave spring is depicted in FIG. 1C, other suitablemethods of loading the system are contemplated.

Wave spring 170 may also apply force to saddle body 160 which results ina friction fit between saddle body 160, retention ring 150, and slide140. This necessitates light force being applied to enable rotation ofsaddle body 160 about slide 140. The friction fit enables adjustments tobe made while eliminating fiddle factor of components inadvertentlymoving.

Operation

Occipital plate 110 supports one or more rod attachment assemblies 130.Although FIGS. 1A, 1B, and 1C illustrate embodiments with two clampingassemblies, embodiments with a single clamping assembly and embodimentswith three or more clamping assemblies are contemplated. Occipital plate110 may be secured to an occiput, and a stabilizing rod (not shown) maybe secured in one or more rod attachment assemblies 130 to providestabilization and/or promote fusion of the occipitocervical junction.

Each rod attachment assembly 130 has at least two states: locked andunlocked. In its unlocked state, each rod attachment assembly 130 ismovably attached to a portion of occipital plate 110 (e.g., rail 117)and may be adjusted positionally prior to locking. For example, rodattachment assembly 130 may be repositioned laterally by sliding rodattachment assembly 130 along a portion of occipital plate 110. Rodattachment assembly 130 may be repositioned rotationally, for example,by turning rod attachment assembly 130 about an axis substantiallyorthogonal to occipital plate 110. In its unlocked state, a rodattachment assembly may be prevented from disconnecting completely froman occipital plate, for example by a retaining element located on theoccipital plate or on the rod attachment assembly. For example, rodattachment assembly 130 may be prevented from disconnecting completelyfrom rail 117 of occipital plate 110 by retaining pin 120 located at thedistal end of rail 117.

In some embodiments, an unlocked rod attachment assembly 130 may befully disconnected from an occipital plate. According to someembodiments, rod attachment assembly 130 may be configured with aloading component to positionally stabilize unlocked rod attachmentassembly 130, allowing for positioning (e.g., more precise positioning)prior to locking.

Once rod attachment assembly 130 is properly positioned, rod attachmentassembly 130 may be locked in place. Once locked, rod attachmentassembly 130 is rigidly fixed to occipital plate 110, and furtherlateral and rotational movement of rod attachment assembly 130 relativeto occipital plate 110 is precluded. Locking occurs when a stabilizingrod (not shown) is inserted into rod attachment assembly 130. Theadjustability of rod attachment assembly 130 relative to occipital plate110 prior to locking, along with the simplicity of the lockingprocedure, allows the installation of occipitocervical fixation assembly100 to be quickly and easily customized to accommodate variations inpatient anatomy as well as variations in desired therapeutic benefits.

Clamp assembly variants may incorporate ball bearings to secure a saddlebody to a slide body or may have a band welded to a portion of a saddlebody. According to some embodiments, a retention ring (e.g., ring 150)may replace such balls, for example, to reduce or eliminate localizedloading, reduce the height (h) of rod attachment assembly, and/or toimprove engagement between a saddle body and a slide 140 since therecess to house a retention ring is smaller than the cavity needed toaccommodate balls.

As shown in FIGS. 2-4, the fixation apparatus may impact the height (h)that a clamp assembly rises above an upper surface of an associatedplate. Rod attachment assembly 200, which includes a retention ring, hasthe smallest height (h). Clamp assembly 300 with ball bearings, has anintermediate height (h). Clamp assembly 400 with ball bearings, is thetallest. As shown, rod attachment assemblies 200, 300, and 400accommodate plates having the same thickness. The overall height ofassembly 200 was reduced with a design that increases the strength ofthe assembly while incorporating a stiffer plate.

To construct an embodiment of rod attachment assembly 130, wave spring170 and pressure cap 180 may be positioned within axial channel 161 ofsaddle body 160. Retention ring 150 may be inserted in slide body recess141. Saddle body 160 may be inserted into slide body 140 and retentionring 150 until saddle body recess 165 is engaged. Rod attachmentassembly 130 may be mounted on plate body 110 by sliding it onto rail117. Retention pin 120, if present, should be in an undeployed positionwhile rod attachment assembly 130 is mounted and subsequently installedand/or moved to a deployed position.

As constructed, rod attachment assembly 130 in its unlocked stateloosely encloses a portion of rail 117 and may be repositioned bysliding rod attachment assembly 130 along a portion of rail 117. In someembodiments, rod attachment assembly 130 may be repositioned at discretepoints along rail 117; in other embodiments, rod attachment assembly 130may be infinitely repositionable along rail 117. In some embodiments,rod attachment assembly 130 may be slid off the end of rail 117 and thusfully disconnected from rail. Rod attachment assembly 130 may be slidbetween two locations along rail 117 but a retaining element (e.g.,retention pin 120) may prevent rod attachment assembly 130 from slidingoff the end of rail 117. In its unlocked state, rod attachment assembly130 may also be repositioned rotationally. Such rotational repositioningallows for varying the angle at which a stabilizing rod inserted in slot163 is positioned relative to rail 117.

According to some embodiments, a saddle body may be rotationallyrepositioned at discrete points throughout 360° of potential rotationalfreedom. In some embodiments, a saddle body may be infinitelyrepositionable throughout 360° of potential rotational freedom. In someembodiments, rod attachment assembly 130 may be rotationallyrepositioned in a finite number of positions; in other embodiments, rodattachment assembly 130 may be infinitely rotationally repositioned.

Both the lateral and rotational position of rod attachment assembly 130may be locked by introducing a stabilizing rod (not shown) into slot163. Locking threads 162 prevent the stabilizing rod from exiting slot163, and in some embodiments a locking nut, locking cap, or othercomponent (not shown) may be employed to secure the stabilizing rod inslot 163. In some embodiments, rod attachment assembly 130 is stillfully or partially adjustable after the insertion of the stabilizingrod, but not after the stabilizing rod is fully secured. Exemplaryapparatus that may be utilized to lock the rod within slot 163 aredescribed in U.S. Pat. Nos. 6,540,748 and 8,062,339 and U.S. PublishedPatent Application No. 2010/0256681, each of which is owned byBlackstone Medical, Inc. and are hereby incorporated by reference.

A secured stabilizing rod in slot 163 contacts and exerts a force uponpressure cap 180, causing pressure cap 180 to exert a force upon the topsurface of rail 117, pulling slide body 140 into contact with rail 117.This immobilizing force locks the position of rod attachment assembly130 both laterally and rotationally, effectively locking the position ofthe stabilizing rod relative to the occipital plate with no directcontact between the stabilizing rod and slide body 140. In theembodiment of FIG. 1C, pressure cap 180 is a rod-to-plate locking pinlocated between saddle body 160 and rail 117.

Although the present invention has been described in detail, it shouldbe understood that various changes, substitutions, and alterations canbe made without departing from the spirit and scope of the invention asdefined by the appended claims. Various terms used herein have specialmeanings within the present technical field. Whether a particular termshould be construed as such a “term of art” depends on the context inwhich that term is used. “Connected to,” “coupled to,” “secured to,” “incontact with,” or other similar terms should generally be construedbroadly. These and other terms are to be construed in light of thecontext in which they are used in the present disclosure and as thoseterms would be understood by one of ordinary skill in the art wouldunderstand those terms in the disclosed context. The above definitionsare not exclusive of other meanings that might be imparted to thoseterms based on the disclosed context.

Words of comparison, measurement, and timing such as “at the time,”“equivalent,” “during,” “complete,” and the like should be understood tomean “substantially at the time,” “substantially equivalent,”“substantially during,” “substantially complete,” etc., where“substantially” means that such comparisons, measurements, and timingsare practicable to accomplish the implicitly or expressly stated desiredresult.

Additionally, the section headings herein are provided for consistencywith the suggestions under 37 C.P.R. 1.77 or otherwise to provideorganizational cues. These headings shall not limit or characterize theinvention(s) set out in any claims that may issue from this disclosure.Specifically and by way of example, although the headings refer to a“Technical Field,” such claims should not be limited by the languagechosen under this heading to describe the so-called technical field.Further, a description of a technology in the “Background” is not to beconstrued as an admission that technology is prior art to anyinvention(s) in this disclosure. Neither is the “Summary” to beconsidered as a characterization of the invention(s) set forth in issuedclaims. Furthermore, any reference in this disclosure to “invention” inthe singular should not be used to argue that there is only a singlepoint of novelty in this disclosure. Multiple inventions may be setforth according to the limitations of the multiple claims issuing fromthis disclosure, and such claims accordingly define the invention(s),and their equivalents, that are protected thereby. In all instances, thescope of such claims shall be considered on their own merits in light ofthis disclosure, but should not be constrained by the headings herein.

As will be understood by those skilled in the art who have the benefitof the instant disclosure, other equivalent or alternative compositions,devices, methods, and systems for stabilizing the occipitocervicaljunction and the cervical spine can be envisioned without departing fromthe description contained herein. Accordingly, the manner of carryingout the disclosure as shown and described is to be construed asillustrative only.

Persons skilled in the art may make various changes in the shape, size,number, and/or arrangement of parts without departing from the scope ofthe instant disclosure. For example, the position and number of rodattachment assemblies may be varied. In some embodiments, plates,retention pins, rod attachment assemblies, slide bodies, retentionrings, saddle bodies, loading components, and/or pressure caps may beinterchangeable. Interchangeability may allow fit to a subject to becustom adjusted. In addition, the size of a device and/or system may bescaled up (e.g., to be used for adult subjects) or down (e.g., to beused for juvenile subjects) to suit the needs and/or desires of apractitioner. Each disclosed method and method step may be performed inassociation with any other disclosed method or method step and in anyorder according to some embodiments. Where the verb “may” appears, it isintended to convey an optional and/or permissive condition, but its useis not intended to suggest any lack of operability unless otherwiseindicated. Persons skilled in the art may make various changes inmethods of preparing and using a composition, device, and/or system ofthe disclosure. For example, a composition, device, and/or system may beprepared and or used as appropriate for animal and/or human use (e.g.,with regard to sanitary, infectivity, safety, toxicity, biometric, andother considerations).

Also, where ranges have been provided, the disclosed endpoints may betreated as exact and/or approximations as desired or demanded by theparticular embodiment. Where the endpoints are approximate, the degreeof flexibility may vary in proportion to the order of magnitude of therange. For example, on one hand, a range endpoint of about 50 in thecontext of a range of about 5 to about 50 may include 50.5, but not 52.5or 55 and, on the other hand, a range endpoint of about 50 in thecontext of a range of about 0.5 to about 50 may include 55, but not 60or 75. In addition, it may be desirable, in some embodiments, to mix andmatch range endpoints. Also, in some embodiments, each figure disclosed(e.g., in one or more of the examples, tables, and/or drawings) may formthe basis of a range (e.g., depicted value +/− about 10%, depicted value+/− about 50%, depicted value +/− about 100%) and/or a range endpoint.With respect to the former, a value of 50 depicted in an example, table,and/or drawing may form the basis of a range of, for example, about 45to about 55, about 25 to about 100, and/or about 0 to about 100.

All or a portion of a device and/or system for stabilizing theoccipitocervical junction and the cervical spine may be configured andarranged to be disposable, serviceable, interchangeable, and/orreplaceable. These equivalents and alternatives along with obviouschanges and modifications are intended to be included within the scopeof the present disclosure. Accordingly, the foregoing disclosure isintended to be illustrative, but not limiting, of the scope of thedisclosure as illustrated by the appended claims.

What is claimed is:
 1. A method of constructing an implantableorthopedic assembly comprising an occipital plate, at least one railrigidly coupled to and extending laterally from the occipital plate, andat least one repositionable rod attachment assembly enclosing a portionof the at least one rail, the at least one repositionable rod attachmentassembly adapted for securing a received portion of a stabilizing rod,the method comprising: positioning a pressure cap of the repositionablerod attachment assembly within a receptacle of a saddle body of the atleast one repositionable rod attachment assembly; positioning a surfaceof the at least one rail against a surface of a slide body of the atleast one repositionable rod attachment assembly; installing a retentionring in the slide body; uniting the saddle body with the slide body,wherein the at least one rail contacts the pressure cap; and securingthe slide body to the saddle body with the retention ring.
 2. The methodof claim 1, further comprising positioning a loading component betweenthe pressure cap and the saddle body of the at least one repositionablerod attachment assembly, wherein the loading component is adapted toexert a bias on the pressure cap against the at least one rail tostabilize the at least one repositionable rod attachment assembly at anadjustable rail position and in an adjustable body position.